Audi TT Quattro 2000-2006 L4 1.8L Timing Belt Should Be Replaced with; Upgraded Composite Impeller. Audi A4 Quattro 2001-2005 L4 1.8L Timing Belt Should Be Replaced with; Upgraded Composite Impeller. VW Beetle 1999-2005 L4 1.8L Upgraded Composite Impeller.